Hi all, I have an usb-storage device in my Computer hat can handle several memory-cards like CF, SD, MMC, MS and SM Cards.
I often read/write to my 1 gig SD card (USB 2.0). Reading is always
fast (~ 5MB/s) using Kernel 2.6.12 or 2.6.13.
But: Writing to the card is very very slow: < 40 kb/s.
My kubuntu system mounts that kind of devices like that:
/dev/sda1 on /media/sda1 type vfat
(rw,noexec,nosuid,nodev,sync,quiet,uid=1000,gid=1000,umask=077,iocharset=utf8)
Now I discovered that if I do a "mount -o remount,async /meda/sda1",
the writing speed increases to a normal value of about 5 megs/s.
I remember, that the problem did not exist with earlier kernels
(and this version of kubuntu)
I think this might be a kernel bug introduced by some patch applied before
2.6.12.
--------------------------------------------------------------------
Demo (1GB SD-Card): I created a 10MB file and tested with that:
mounted as shown above (with 'sync')
[EMAIL PROTECTED]:~ # dd if=/dev/zero of=./big_file bs=1M count=10
10+0 records in
10+0 records out
10485760 bytes transferred in 0.032557 seconds (322073583 bytes/sec)
[EMAIL PROTECTED]:~ # time cp big_file /media/sda1
real 4m30.353s
user 0m0.000s
sys 0m0.392s
[EMAIL PROTECTED]:~ #
[EMAIL PROTECTED]:~ # mount /media/sda1 -o remount,async
[EMAIL PROTECTED]:~ # dd if=/dev/zero of=./big_file2 bs=1M count=10
10+0 records in
10+0 records out
10485760 bytes transferred in 0.032355 seconds (324085870 bytes/sec)
[EMAIL PROTECTED]:~ # time { cp big_file2 /media/sda1; sync; }
real 0m2.048s
user 0m0.000s
sys 0m0.108s
[EMAIL PROTECTED]:~ #
(38 kb/s vs. 5 MB/s !!)
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Demo 2 (1GB CF-Card)
Using a CF-Card, the problem is still there, but the difference is
not that big:
[EMAIL PROTECTED]:~ # time cp big_file /media/sda1
real 0m18.770s
user 0m0.000s
sys 0m0.136s
[EMAIL PROTECTED]:~ # mount /media/sda1 -o remount,async
[EMAIL PROTECTED]:~ # time { cp big_file2 /media/sda1; sync; }
real 0m5.970s
user 0m0.000s
sys 0m0.088s
[EMAIL PROTECTED]:~ #
(548 kb/s vs. 1715 kb/s)
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Here some more detailed informartion about my setup:
Kernel: vanilla 2.6.13
USB modules:
hci_usb 12680 6
usbhid 34848 0
usb_storage 76608 1
usbcore 127996 6
ehci_hcd 35016 0
uhci_hcd 34640 0
USB Devices shown by lspci -v:
0000:00:10.0 USB Controller: VIA Technologies, Inc. VT82xxxxx UHCI
USB 1.1 Controller (rev 81) (prog-if 00 [UHCI])
Subsystem: Asustek Computer, Inc. A7V600 motherboard
Flags: bus master, medium devsel, latency 64, IRQ 20
I/O ports at cc00 [size=32]
Capabilities: [80] Power Management version 2
0000:00:10.1 USB Controller: VIA Technologies, Inc. VT82xxxxx UHCI
USB 1.1 Controller (rev 81) (prog-if 00 [UHCI])
Subsystem: Asustek Computer, Inc. A7V600 motherboard
Flags: bus master, medium devsel, latency 64, IRQ 20
I/O ports at dc00 [size=32]
Capabilities: [80] Power Management version 2
0000:00:10.2 USB Controller: VIA Technologies, Inc. VT82xxxxx UHCI
USB 1.1 Controller (rev 81) (prog-if 00 [UHCI])
Subsystem: Asustek Computer, Inc. A7V600 motherboard
Flags: bus master, medium devsel, latency 64, IRQ 20
I/O ports at ec00 [size=32]
Capabilities: [80] Power Management version 2
0000:00:10.3 USB Controller: VIA Technologies, Inc. VT82xxxxx UHCI
USB 1.1 Controller (rev 81) (prog-if 00 [UHCI])
Subsystem: Asustek Computer, Inc. A7V600 motherboard
Flags: bus master, medium devsel, latency 64, IRQ 20
I/O ports at b000 [size=32]
Capabilities: [80] Power Management version 2
0000:00:10.4 USB Controller: VIA Technologies, Inc. USB 2.0 (rev 86)
(prog-if 20 [EHCI])
Subsystem: Asustek Computer, Inc. A7V600 motherboard
Flags: bus master, medium devsel, latency 64, IRQ 20
Memory at fda00000 (32-bit, non-prefetchable) [size=256]
Capabilities: [80] Power Management version 2
Any hints anybody?
Did I miss some important information?
Thanks in advance for helping.
-Marc
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